FIG. 1 is a sectional view of the conventional information recording medium (hereinafter referred to as a recording medium), for example, a magnetic recording tape, disclosed in, for example, "AUDIO HANDBOOK" (published from Ohm Publishing Co. in 1978). In this figure, reference numeral 1 represents a base and reference numeral 2 represents a magnetizable layer coated on the base 1. The base 1 is prepared from, for example, cellulose acetate, polyvinyl chloride, polyester, etc., and the magnetizable layer 2 is in the form of a lacquer made of, as a principal component, a needle-shaped powder of iron oxide generally referred to as gamma hematite (.gamma.-Fe.sub.2 O.sub.3). FIG. 2 is an explanatory diagram showing the manner in which information is recorded on and reproduced from this magnetic recording tape. In this figure, reference numeral 3 represents a coil, reference numeral 4 represents a core and reference numeral 5 represents a gap, the coil 3, the core 4 and the gap 5 altogether forming a magnetic recording and/or reproducing head. The arrow A represents the direction of movement of the tape and the arrow B represents the direction of flow of an electric current. The operation will now be described.
The operation which takes place when information is recorded on the magnetic tape will be described with particular reference to FIG. 2(a). When an electric current i of such a waveform as show is allowed to flow through the coil 3, a leakage magnetic field is produced across the gap 5. By the action of this leakage magnetic field, the magnetizable layer 2 of the magnetic tape is magnetized to N-S. Since the magnetic tape is transported in the direction of the arrow A, information is successively recorded thereon as it moves. The operation which takes place when the information on the magnetic tape is reproduced from the magnetic tape will be described with particular reference to FIG. 2(b). The magnetic field generated as a result of the magnetization of the magnetizable layer 2 to N-S exists in the vicinity of the magnetic tape. During the movement of the magnetic tape in the direction of the arrow A, the magnetic flux passes the gap 5 and permeates into the magnetic head. By this magnetic flux, an induced voltage e is induced in the coil 3 as shown according to Faraday's law.
In the conventional recording medium constructed as hereinbefore described, the distance between N and S poles shortens with increasing recording density. With the shortened distance between N and S poles, an enhanced degaussing action occurs as a result of the presence of a diamagnetic field and, therefore, magnetization becomes difficult. Accordingly, the recording density of the magnetic recording medium has been limited because of this degaussing action.
The present, invention has been developed in an effort to eliminate the above discussed problem and is intended to provide a recording medium and methods of recording and reproducing information on and from the recording medium, respectively, wherein the recording density can be increased as compared with that in the conventional magnetic recording medium.